The invention relates to a circuit arrangement for amplifying pulsed signals.
In particular, wide band optical systems for transmitting information are suitable for transmitting constantly increasing quantities of information, in which systems the information is passed in the form of light pulses by means of optical waveguides. Directly modulated semiconductor lasers are to be used as light emitters and avalanche photo diodes as light receivers. So-called repeater stations are arranged at certain intervals in the transmission path for amplifying and regenerating transmitted pulse sequences. In such a repeater station incoming pulses of light are transformed first into electrical signals by means of a light receiver; these are then regenerated and amplified. A light emitter is again controlled with the processed electrical pulses so that at the output of the repeater station light signals are again ready for further conduction in an optical waveguide. Optical waveguides have a very high bandwidth; it may be envisaged that data flows of several gigabits per second may be transmitted on a single optical waveguide in the form of a glass fibre with the fineness of a hair. Thus, however, problems occur in signal processing in the repeater stations because the speed of conventional electronic circuits is insufficient for processing these data flows.
Amplifier circuits with semiconductor diodes are already known from IRE TRANSACTIONS ON ELECTRON DEVICES, 6 (1959), 341-347; these have, however, a relatively low high-end cutoff frequency.